The present invention relates generally to polymeric materials and more particularly to polyesters, as well as methods for making and degrading polyesters. The invention also relates to a mixed culture of microorganisms that is able to degrade polymers containing a hydrolyzable backbone polyester and a method for making this mixed culture of microorganisms.
The majority of plastic materials available today are made from petroleum. Such petroleum-based plastics are difficult to degrade, biologically or otherwise. Because of the extensive use of petroleum-based plastics by both consumers and industry, a considerable amount of waste is created. This causes ecological problems because the waste is stored in landfills and other waste disposal systems and accumulates without degradation. Furthermore, petroleum is an expensive component of plastic.
Biodegradable polymers have been synthesized to provide alternatives to petroleum-based plastics. They are often synthesized from starch, sugar, natural fibers or other organic biodegradable components in varying compositions. However, such biodegradable polymers often lack desirable physical characteristics, and this limits their use to specific situations. Many biodegradable polymers are blended polymers or composite polymers and thus do not have uniform mechanical properties. Still further, most known biodegradable polymers are aliphatic polyesters that have low softening points (T.sub.m), which prevents their use as a material in a variety of fields.
In order to overcome the deficiencies found with conventional plastics and biodegradable polymers, a degradable polymer having enhanced strength and flexibility and a method for making such a degradable polymer are needed for a variety of applications. Still further, a polymer that is made from organic substances rather than petroleum-based compounds and a method for making this polymer are needed. In addition, certain formulations of this polymer should be biodegradable. A mixed culture of microorganisms that can be used to degrade the polymers of the present invention and other polymers and a method for making this mixed culture are also needed.